Spring tooth harrow

ABSTRACT

A spring tooth harrow comprising an elongated tool bar having a plurality of harrow sections secured thereto by adjustable mounting brackets to enable the harrow section to be raised or lowered with respect to the draw bar. Each harrow section includes a pair of longitudinally extending arms which are pivotally secured to the mounting brackets and which are urged downwardly with respect thereto by pairs of springs. Fork pipes are rotatably mounted on the arms and extend therebetween and have spring teeth secured thereto. The pipes may be rotatably moved in unison to change the angle of attack of the spring teeth or the forwardmost pipe may be independently rotated with respect to the remaining pipes so that the angle of attack of the forwardmost spring teeth may be varied with respect to the trailing spring teeth.

This is a continuation application of Ser. No. 08/016,791, filed Feb.11, 1993, now U.S. Pat. No. 5,358,056, which was a continuation-in-partapplication of application Ser. No. 07/725,342, filed Jul. 3, 1991, nowabandoned.

BACKGROUND OF THE INVENTION

This invention relates to a spring tooth harrow and more particularly toa spring tooth harrow including novel means for mounting the harrow on apivotal draw bar and novel means for pressurizing the harrow sectionsand for maintaining the harrow sections in a substantially verticallydisposed position during transport.

Conventional spring tooth harrows normally consist of an elongated,pivotal draw bar having a plurality of harrow sections mounted thereonso as to trail the draw bar. Normally, the harrow sections are connectedto the draw bar by means of flexible chains or the like. Onedisadvantage of the prior art harrows is that the harrow sections tendto bounce when being pulled through the field. A further disadvantage ofthe conventional harrows is that the spring teeth thereof are not ableto adequately penetrate the soil. Still another disadvantage of theprior art harrows is that there is normally not a convenient means forchanging the attack angle of the spring teeth.

A further disadvantage of the prior art harrows is that when the drawbar is pivoted and folded to its transport position, the chain supportedsections "bounce around" when the harrow is transported from onelocation to another.

Therefore, it is the principal object of the invention to provide animproved spring tooth harrow.

A further object of the invention is to provide a spring tooth harrowincluding novel means which permits the harrow to be selectivelyvertically adjustably mounted on the draw bar so that the harrow sectionmay be lowered relative to the draw bar as the spring teeth wear.

Still another object of the invention is to provide a spring toothharrow including novel means for pressurizing the harrow section so asto avoid section bounce and so as to ensure maximum tooth penetration.

Still another object of the invention is to provide a spring toothharrow including novel means for pressurizing the harrow section withthe pressurizing means also serving to maintain each harrow section in asubstantially vertically disposed position when the draw bar is pivotedand folded to its transport position.

Yet another object of the invention is to provide a spring tooth harrowincluding means for maintaining each harrow section in a substantiallyvertically disposed position when the draw bar is pivoted to itstransport position.

Still another object of the invention is to provide a spring toothharrow including means for adjusting the front row of spring teethrelative to the remaining rows of spring teeth for each section.

These and other objects of the present invention will be apparent tothose skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of the spring tooth harrow of this invention;

FIG. 2 is a perspective view of one end of one harrow section;

FIG. 3 is a partial top view of one end of one harrow section;

FIG. 4 is a side view of one of the harrow sections;

FIG. 5 is a perspective view of the means for mounting one end of theharrow section to the tool bar;

FIG. 6 is a side elevational view illustrating the means by which oneharrow section is secured to the tool bar; and

FIG. 7 is a partial side view illustrating the harrow sections in asubstantially vertically disposed position after the draw bar has beenpivoted or rotated to its transport position.

SUMMARY OF THE INVENTION

An improved spring tooth harrow is described comprising an elongated,pivotal draw bar having a plurality of the harrow sections of thisinvention mounted thereon. Each of the harrow sections includes a pairof mounting brackets at the forward end thereof which are selectivelyvertically adjustably mounted on the draw bar so that the mountingbracket may be lowered relative to the draw bar as the harrow teethbecome worn. A pair of support arms are typically connected to themounting brackets and include a spring means so that the harrow sectionwill be pressurized to prevent harrow section bounce and to ensure thatthe spring teeth will adequately penetrate the soil. A plurality oftransversely extending tooth supports are rotatably or pivotally mountedon the support arms and may be pivoted with respect thereto to changethe angle of attack of the spring teeth. The forward most row of springteeth may be pivoted relative to the remaining rows of spring teeth. Thespring means also serves to maintain the harrow sections in a wellsupported, substantially vertically disposed position when the draw baris pivoted or rotated to its transport position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The spring tooth harrow of this invention is referred to generally bythe reference numeral 10 and is designed to be pulled behind a tractoror the like to harrow the soil. Most spring tooth harrows include anelongated transversely extending draw bar 12 to which the various harrowsections 14 are connected. Draw bar 12 is of conventional design andincludes a center section 12A supported by wheels W₁ and W₂. Wingsection 12B and 12C are pivotally connected to the outer ends of centersection 12A in conventional fashion. Wheels W₃ and W₄ support the endsof the wing sections 12B and 12C respectively when the draw bar 12 is inits field position of FIG. 1. The axis of each of the pivotalconnections between the center section 12A and the wing sections 12B and12C wheels dwells in a horizontal plane transverse to the longitudinalaxis of draw bar 12 when the draw bar 12 is in the field position ofFIG. 1.

Draw bar 12 is rotatable or pivotal with respect to hitch H byconventional means to enable draw bar 12 to be selectively moved betweenthe field position of FIG. 1 to the transport position of FIG. 7 so thatthe harrow sections may be raised from the ground. As seen in thedrawings, a hydraulic cylinder HC is mounted on hitch H and has itscylinder rod connected to post P. Post P is connected to center section12A of draw bar 12 by means of a linkage L. Thus, extension of thecylinder rod of the hydraulic cylinder HC causes draw bar 12 to berotated from the field position to the transport position. Conversely,retraction of the cylinder rod of hydraulic cylinder HC causes the drawbar 12 to be moved from its transport position of FIG. 7 to the fieldposition of FIG. 1. When the draw bar 12 is moved to its transportposition, wheels W₅ and W₆ are lowered into ground engagement inconventional fashion to enable the wing sections 12B and 12C to befolded rearwardly with respect to center section 12A to reduce the widthof the harrow for transport in conventional fashion. The spring toothharrow of this invention may be conveniently attached to almost everytype of draw bar and can be supplied as a replacement for worn harrowsections. Thus, such an invention will not always be sold with a drawbar since the harrow section of this invention can be convenientlyattached to square or rectangular draw bars.

Each of the harrow sections 14 comprises a pair of spaced-apart mountingbrackets 16 and 18 which are selectively vertically adjustably mountedto the draw bar by means of conventional bolts and clamps. Inasmuch aseach of the mounting brackets 16 and 18 are identical, only mountingbracket 16 will be described in detail.

Mounting bracket 16 includes a pair of vertically disposed bracketmembers 20 and 22 which are L-shaped. Bracket member 20 includes a flatfront portion having a flat rear portion extending rearwardly therefrom.The flat front portion is provided with a plurality of bolt openings 28formed therein to permit the bracket member to be selectively verticallyadjustably mounted on the draw bar. Similarly, bracket member 22includes a fiat front portion 30, flat rear portion 32 and bolt openings34 in flat portion 30. Spacer bolts 36, 38 and 40 extend between theflat rear portions 26 and 32 and have collars 41a, 41b and 41c mountedthereon between the rear portions 26 and 32 to maintain the horizontalspacing therebetween. The forward end of arm 42 is pivotally connectedto mounting bracket 16 as seen in the drawings by means of bolt 44.Bolts 36 and 40 also limit the pivotal movement of arm 42 with respectto bracket 16 as will be described in greater detail hereinafter.

Ear 46 is welded to the upper surface of arm 42 and has an adjustmentbolt 48 extending therethrough. Angle 50 is mounted on the forward endof adjustment bolt 48 and is disposed transversely to the longitudinalaxis of arm 42 as seen in FIG. 5. Springs 52 and 54 are secured at theirupper ends to angle 50 and are secured at their lower ends to theopposite ends of bolt 56 which is secured to and which extends betweenthe lower rearward ends of flat rear portions 26 and 32. The adjustmentof bolt 48 changes the tension in the springs 52 and 54 to vary theamount of downward yieldable pressure exerted on the forward end of arm42. Arm 58 is identical to arm 42 and is pivotally connected to bracket18. Arms 42 and 58 are provided with a plurality of U-shaped straps 60welded to the underside thereof in which are rotatably received thesupport pipes 62, 64, 66, and 68. A plurality of spring teeth 70 aresecured to each of the support pipes 62 and includes shank portion 72which extends downwardly from coiled portion 74. Bars 76, 78, 80 and 82are welded to pipes 62, 64, 66 and 68 respectively and extend upwardlytherefrom. Link 84 pivotally connects the upper ends of bars 78, 80 and82. Link 86 adjustably connects the upper ends of bars 76 and 78 as seenin the drawings. Thus, the bars 76, 78, 80 and 82 are moved in unison bythe links 84 and 86 when the links 84 and 86 are connected. Movement ofthe bars 76, 78, 80 and 82 causes rotation of the support pipes 62, 64,66 and 68 respectively so as to change the angle of attack of the shankportions of the spring teeth. Links 84 and 86 are maintained in positionby means of arm 88 which it pivotally connected at its rearward end toear 90 welded to the upper side of the rearward end of arm 42. Theforward end of arm 88 is adjustably secured to the bolt 92 whichconnects the upper end of bar 80 with link 84. Thus, when bolt 92 isremoved, the bars 76, 78 and 82 may be pivoted in unison to the desiredposition and then held in that position by reinstalling bolt 92 throughbar 80, link 84 and the forward end of arm 88. The bar 80 andcorresponding pipe 66 is obviously moved to correspond with the othertubes 62, 64, 68 so that the bolt 92 can be reinserted to hold thedesired position of all the pipes.

The various harrow sections are secured to the draw bar 12 by thebrackets 16 and 18. As the spring teeth become worn, the brackets 16 and18 may be lowered with respect to the draw bar to effectively lower thelower ends of the shank portions of the spring teeth 70. During fieldoperation, the springs 52 and 54 urge arm 42 downwardly with respect tothe mounting bracket 16 so as to prevent harrow bounce and so as toforce the spring teeth into the soil which is being harrowed. Thesprings associated with bracket 18 similarly urge arm 58 downwardly withrespect to the mounting bracket 18.

If it is desired to have the angle of attack of all of the harrow teethto be the same, bolt 94 is left in position and the bolt 92 is removed.Bars 84 and 86 are then moved in unison to cause the pipes 62, 64 and 68to rotate within their straps 60 in unison. When the teeth have beenpositioned as desired, the bolt 92 is then reinserted through one of theopenings 98 in arm 88 after the bar 80 is moved to correspond with theother bars. It if is desired to change the angle of attack of the springteeth on pipe 62 with respect to the remaining pipes, bolt 94 is removedto permit pipe 62 to be rotated independently of the remaining pipesthereby permitting angle of attack of the spring teeth on the pipe 62 tohave a different angle than the remaining teeth. Many farmers preferthat the shank portions 72 on teeth 70 on the pipe 62 extend rearwardlyat a greater angle than the spring teeth on the remaining pipes so as tobe better able to penetrate through trash or stubble on the ground beingharrowed.

As seen in FIG. 7, when draw bar 12 has been moved to its transportposition, the harrow sections are positioned in a substantiallyvertically disposed position. The springs 52 yieldably maintain theharrow sections in the transport position of FIG. 7 to prevent theharrow sections from "bouncing around" as is the case with chainsupported harrow sections. This is accomplished by the springs 52 urgingthe arms 42 and 58 rearwardly against the collars 42c on bolts 40.Further, the bolts 36 and 40 on each mounting bracket also limit themovement of the associated arms 42 to maintain the arms 42 in asubstantially vertically disposed position.

Thus it can be seen that the invention accomplishes at least all of itsstated objectives.

I claim:
 1. In combination:a tractor having a hitch extending rearwardlytherefrom; an elongated, horizontally disposed and transverselyextending draw bar operatively secured to said hitch and having rearwardand forward sides; said draw bar being wheel supported and beingpivotally movable, about a horizontal axis with respect to said hitch toenable the draw bar to be pivoted from a field position to a transportposition; means for pivoting said draw bar from said field position tosaid transport position; a plurality of harrow sections secured to saiddraw bar and extending rearwardly therefrom; each of said harrowsections including at least first and second horizontally spacedmounting brackets which are secured to said draw bar; first and secondarms pivotally connected at their forward ends to said first and secondmounting brackets respectively, said first and second arms extendingrearwardly therefrom; a resilient means interconnecting each of saidarms with its respective mounting bracket for yieldably maintaining theharrow section in ground engagement; a plurality of horizontally spacedtooth supports selectively rotatably mounted on the underside of saidarms and extending therebetween; a plurality of spring teeth operablysecured to said tooth supports and extending downwardly therefrom; aselectively movable linkage means interconnecting said tooth supports sothat said tooth supports may be rotated as a unit; an adjustment memberpivotally connected at one end to one of said arms, and selectivelyadjustably connected at an opposite end to said linkage means, forselectively fixing said linkage means in a pre-determined position; saidtooth supports including a forward tooth support, a rearward toothsupport, and at least one intermediate tooth support; said linkage meansincluding means for selectively rotatably moving said forward toothsupport with respect to the other tooth supports; a stop associated witheach of said mounting brackets for limiting the pivotal movement of theassociated arm so that when said draw bar is moved to its said transportposition, said stop limits the forward pivotal movement of saidrespective arm and the tooth supports secured thereto.
 2. A spring toothharrow, comprising,an elongated, horizontally disposed and transverselyextending draw bar having rearward and forward sides; said draw barbeing wheel supported and having a hitch extending forwardly therefromfor attachment to a tractor; said draw bar being selectively pivotallymounted, about a horizontal axis, to said hitch, whereby said draw barmay be pivoted from a field position to a transport position; means forpivoting said draw bar from its field position to its transportposition; a plurality of harrow sections operatively secured to saiddraw bar and being positioned rearwardly thereof; mounting meanssecuring said harrow sections to said draw bar; said mounting meansincluding a resilient means for yieldably maintaining the associatedharrow section in ground engagement and to yieldably maintain theassociated harrow section in a substantially vertically disposedposition when said draw bar is moved to its transport position; each ofsaid harrow sections including at least a pair of horizontallyspaced-apart arms which extend rearwardly with respect to said draw bar;a plurality of horizontally spaced tooth supports selectively rotatablymounted on the underside of said arms and extending therebetween; aplurality of spring teeth operably secured to said tooth supports andextending downwardly therefrom; a selectively movable linkage meansinterconnecting said tooth supports so that said tooth supports may berotated as a unit; an adjustment member pivotally connected at one endto one of said arms, and selectively adjustably connected at an oppositeend to said linkage means, for selectively fixing said linkage means ina pre-determined position; said tooth supports including a forward toothsupport, a rearward tooth support, and an intermediate tooth support;said linkage means including means for selectively rotatably moving saidforward tooth support with respect to the other tooth supports.